This community calls itself "board and card games" but refuses to answer a simple question like the one in the title so I'm looking for a site where I can ask something like this.
From this site's FAQ:
You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page.
Your questions should be reasonably scoped. If you can imagine an entire book that answers your question, you’re asking too much.
If your motivation for asking the question is “I would like to participate in a discussion about _”, then you should not be asking here. However, if your motivation is “I would like others to explain _ to me”, then you are probably OK. (Discussions are of course welcome in our real time web chat.)
So you could try taking it to web chat. Alternatively (I assume you're talking about Magic decks) there are a million other community sites out there. I recommend mtgsalvation.com as one that's busy, friendly and free.
One way to ask this type of question, which seems to be accepted based on this discussion is to generalize and discuss a strategy and perhaps a particular problem you're having with that strategy against certain other strategies.
If you can make your question general enough it regains that sense of being helpful to others, and does, to some degree, make it a little more time resistant since particular cards will come and go but the effect they provide on game play should still tie into the strategy.
With your particular deck you could explain what your strategy is and try to strengthen that strategy or ask how a particular change might work with the strategy.
I don't think there's a comprehensive list of strategies out there, but certainly some are obvious: token swarms, white weenie, direct damage, life gaining, aggro decks, mana producing in dual/tri colours and so on ...
Obviously we're all still trying to find that right side of the fine line where these things fit.
For example asking how to modify a white weenie deck so that it can better compete with a red direct damage aggro deck might be better than providing the white weenie decklist and asking for change suggestions.